A drug taken by up to 100,000 men for enlarged prostate has been linked to breast cancer in men, the UK medicines regulator has said.

By Rebecca Smith, Medical Editor, Telegraph.co.uk
Published: 6:50PM GMT 03 Dec 2009
New warnings will be added to the packaging of Finasteride after five men in Britain taking the drug developed breast cancer.

An analysis by the Medicines and Healthcare products Regulatory Agency found a total of 53 men worldwide on the drug had developed breast cancer.

The report from the MHRA said: "Cases of male breast cancer have been reported for finasteride, and the review suggested that an increased risk of male breast cancer associated with finasteride use cannot be excluded."

"Patients using finasteride products should be advised to promptly report to their doctor any changes in their breast tissue such as lumps, pain or nipple discharge because these may be signs of a serious condition, such as breast cancer."

"On the basis of the review, it was recommended that a warning on the risk of breast cancer should be included in the product information for all medicines containing finasteride."

The drug is used for the treatment of benign prostatic hyperplasia, also known as enlarged prostate, which is not cancerous but does cause symptoms such as difficulty passing urine.

Finasteride is known to cause gynaecomastia in men, the enlargement of male breast tissue, and this is thought to be connected to the reports of breast cancer in men because men who develop the condition are more likely to have their chests checked by doctors.

The condition is found in half of all men aged between 51 and 60 and is more common in older men.

Lord Mandelson received treatment for the condition earlier this year.

It is thought around 100,000 men in England and Wales could be taking finasteride, also known in Britain as Proscar and Propecia.

The drug has been under close review since 1998 works by preventing testosterone from being used by the body and this shrinks the prostate gland.

Less than one per cent of the 45,500 cases of breast cancer diagnosed each year in Britain are in men and the condition is very different in men.

There are around 300 men diagnosed with breast cancer in Britain annually.

Comment: As more evidence accumulates, finasteride looks more and more like a faustian deal. Our primary concerns revolve not only around the oft occurring incidence of sexual side effects and Gyno, but around the documented impact on allopregnenolone and the documented neurological effects.